The Enhancement of Growth, Photosynthetic Rate, Yield, and Physiological Seed Quality of Several Soybean Varieties (Glycine max L.) through ZnSO₄ Application

Soybean (Glycine max L.) productivity and physiological seed quality are influenced by micronutrient availability and genotype. This study evaluated Zn application through seed priming and foliar spraying on growth, photosynthetic rate, yield, and physiological seed quality of Deja 1, Detap 1, and Grobogan. A strip-plot design with three replications was used. Treatments were water priming (P0), 0.5% Zn priming (P1), Zn priming + vegetative foliar spray (P2), Zn priming + generative foliar spray (P3), and Zn priming + vegetative and generative foliar sprays (P4). Data were analyzed by ANOVA followed by LSD at 5%. Zn application significantly affected photosynthetic rate; P1 and P2 reached 27.9 and 28.3 µmol CO₂ m⁻² s⁻¹, respectively, compared with 20.5 in P0. Significant Zn × variety interactions occurred for plant height, leaf number, pod number, seed number, 100-seed weight, seed weight per plant, and normal seedling percentage after accelerated aging. Deja 1-P4 produced 120.27 pods, 247.87 seeds, and 34.58 g seed weight per plant, while Detap 1-P4 and Grobogan-P4 had 84% normal seedlings after aging. These results indicate genotype-dependent responses to Zn and improved physiological vigor indicators following preharvest Zn application.